System to assess activity level of a user

ABSTRACT

A pedometer that records the number of steps over a defined period of time and a moment sensor that records the moments experienced by a prosthesis are used in a networked computer environment to assess the functional activity level and instability of a lower limb amputee. The networked environment may include a user computer and a server computer in communication through the Internet. Both the user computer and the server computer include a functional assessment tool and a stability assessment tool. The tools on the user computer and server computer cooperate in assessing the activity level and the instability of a lower limb amputee. The server computer may further host a Website and a secure online database that provides support to the user including the managing of clients and their medical records.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.61/243,839, filed Sep. 18, 2009, which is fully incorporated hereinexpressly by reference.

BACKGROUND

Advancements in materials have led to a variety of improvements inprostheses, including the use of low weight, high strength materials andenergy storage and release components. The variety of choices inprosthesis components is meant to fit with the variety of lifestyles ledby lower limb amputees. For example, an elderly person that has a lowactivity level may not require the most advanced materials. On the otherhand, a strong and physically active person may desire a prosthesis thatwill withstand a more rigorous lifestyle. Both high and low activityprosthesis wearers require that the prosthesis be matched with theirlifestyle to ensure that the prosthesis improves their quality of life.

In order to properly assess the activity levels of lower limb amputees,the Medicare program administered by the United States Government hasdeveloped an index for assessing an amputee's functional level. TheMedicare system of “K” codes provides a set of categories used todistinguish between activity levels of amputees. In the lowest level,K0, the patient does not have the ability or potential to ambulate ortransfer safely with or without assistance, and a prosthesis does notenhance their quality of life or mobility. In the next lowest level, K1,the patient has the ability or potential to use a prosthesis fortransfers or ambulation on level surfaces at fixed cadence. At the nextlevel, K2, the patient has the ability to traverse low-levelenvironmental barriers such as curbs, stairs, or uneven surfaces. Atlevel K3, the patient has the ability or potential to traverse mostenvironmental barriers and may have vocational, therapeutic, or exerciseactivity beyond basic ambulation. At the highest level, K4, the patienthas the ability or potential for prosthetic ambulation that exceedsbasic ambulation skills, exhibiting high impact, stress, or energylevels.

The clinician treating the amputee patient prescribes a prosthesis byassigning the patient to one of the K codes defining the activity level.A problem arises in that there is no objective way to measure activitylevel. A problem also arises because an overdesigned prosthesis mayresult in imbalance or instability issues for the wearer too weak toproperly control the prosthesis. An underdesigned prosthesis willcurtail the lifestyle of an active wearer due to having to compensatefor a deficient prosthesis. Both situations usually lead to a reductionin the quality of life and rehabilitation of the patient.

Up until the present time, assessing the functionality of an amputeepatient is mostly a subjective evaluation. Based on clinical experienceand without any objective tool, some clinicians may decide tounderprescribe a prosthesis in order to save on costs or because theclinician does not believe that the patient will be fully rehabilitatedto a high functional level. On the other hand, if the clinicianoverprescribes a prosthesis, the prosthesis is overdesigned andunderutilized, thus wasting resources that may be put to better use. Ineither case, overprescription or underprescription of a prosthesis maydiminish the quality of life for the patient, or hamper theirrehabilitation because the prosthesis is not correctly fitted.

Accordingly, a tool is necessary to properly assess the functional levelof activity of a lower limb amputee.

SUMMARY

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This summary is not intended to identify key features ofthe claimed subject matter, nor is it intended to be used as an aid indetermining the scope of the claimed subject matter.

A first embodiment is related to a system for assessing the activitylevel of a lower limb amputee. The system includes a pedometercomprising a sensor to determine a step, a clock to keep track of thetime period that the pedometer is recording steps and a memory to recordthe steps and time, a user computer connected to a network incommunication with a server computer, wherein the user computercomprises a local functional assessment tool that configures thepedometer to record step data and receives recorded step data from thepedometer; and a server computer in communication with the user computerthrough a communication network, wherein the server computer comprises aremote functional assessment tool that receives the step data from theuser computer and processes the data to provide an activity level of theamputee.

In the first embodiment, the server computer may host a Web site thatprovides a service for assessing the functional activity level of alower limb amputee, a client manager tool, and an online database.

In the first embodiment, the remote functional assessment tool mayreceive inputs of a cadence variability, a potential to ambulate, anambulation requirement, and a clinical observation to provide theactivity level of the amputee.

In the first embodiment, the remote functional assessment tool mayprovide a value describing a cadence variability as a variance in theamount of time that the amputee spends at a plurality of levels of steprate in a defined period of time.

In the first embodiment, the remote functional assessment tool mayprovide a value describing a potential to ambulate as a number of stepstaken by the amputee in a defined period of time.

In the first embodiment, the remote functional assessment tool mayprovide a value describing the ambulation requirement as a maximumnumber of steps taken by the amputee in a defined period of time.

In the first embodiment, the system may further include a dockingstation connected to the user computer, wherein the docking stationcommunicates with the pedometer.

A second embodiment is related to a method for assessing the activitylevel of a lower limb amputee executed using one or more computers. Themethod includes recording the number steps taken by a lower limb amputeeover a defined period of time, calculating a first value describing acadence variability from the recorded steps, calculating a second valuedescribing a potential to ambulate from the recorded steps, calculatinga third value describing an ambulation requirement from the recordedsteps; and calculating an activity level based on at least, the first,second and third values. In the second embodiment, the cadencevariability is described as a variance in the amount of time that theamputee spends at a plurality of levels of step rate in a defined periodof time.

In the second embodiment, the potential to ambulate is described as anumber of steps taken by the amputee in a defined period of time.

In the second embodiment, the ambulation requirement is described as amaximum number of steps taken by the amputee in a defined period oftime.

In the second embodiment, the method may further include obtaining afourth value describing a clinical observation of an activity level, andcalculating an activity level as the average of the first, second, thirdand fourth values.

In the second embodiment, the method may further include obtaining atleast one descriptor selected from the group consisting of the height ofthe amputee, the walking speed of the amputee relative to people ofsimilar height, the quickness of stepping by the amputee, the range ofwalking speeds of the amputee, and the appearance of the leg motion ofthe amputee, and assigning a cadence setting and response to motion fromone or more descriptors.

A third embodiment is related to a method for making a prosthesis. Themethod includes recording on a computer memory the number of steps takenby a lower limb amputee over a defined period of time, inputting therecorded number of steps into one or more computers and calculating anactivity level of a lower limb amputee from the recorded number ofsteps; and assembling a prosthesis with components that are determinedby the calculated activity level.

A fourth embodiment is related to system for assessing the instabilityof a lower limb amputee wearing a prosthesis. The system includes amoment sensor comprising one or more sensors for determining momentsexperienced by the prosthesis in the sagittal and coronal planes, a usercomputer connected to a network in communication with a server computer,wherein the user computer comprises a local stability assessment toolthat receives recorded moment data from the moment sensor, and a servercomputer in communication with the user computer through a communicationnetwork, wherein the server computer comprises a remote stabilityassessment tool that receives the moment data from the user computer andprocesses the data to provide a stability level of the amputee.

In the fourth embodiment, the server computer may host a Web site thatprovides a service for assessing the instability level of a lower limbamputee, a client manager tool, and an online database.

In the fourth embodiment, the remote functional assessment tool mayreceive inputs of moments experienced in the sagittal plane by aprosthesis socket and moments experienced in the coronal plane by aprosthesis socket.

In the fourth embodiment, the remote functional assessment tool mayreceive a model of alignment derived from a set of training data ofsagittal and coronal moments recorded from lower limb prosthesis wearersof a known stability.

A fifth embodiment is related to a method for assessing the instabilityof a lower limb amputee wearing a prosthesis executed using one or morecomputers. The method includes recording the sagittal and coronalmoments experienced by a prosthesis worn by a lower limb amputee,obtaining a model of stability derived from a set of training data thatdescribes the sagittal and coronal moments recorded from lower limbprosthesis wearers of a known stability, calculating a measure of theinstability of the lower limb amputee described as the variance of therecorded moments and the model of alignment.

In the fifth embodiment, a moment sensor coupled to a prosthesis socketmay record the sagittal and coronal moments.

In the fifth embodiment, the method may further include downloadingrecorded sagittal and coronal moments to a user computer incommunication with a server computer.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention will become more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a diagrammatical illustration representing one embodiment ofan environment in which the present invention is used;

FIG. 2 is a diagrammatical illustration of a representative usercomputer used in one embodiment of the present invention;

FIG. 3 is a diagrammatical illustration of a representative servercomputer used in one embodiment of the present invention;

FIG. 4 is a flow diagram of a method to determine functional activitylevel of a lower limb amputee client in accordance with one embodimentof the present invention;

FIG. 5 is a flow diagram of a method to determine stability of a lowerlimb amputee client in accordance with one embodiment of the presentinvention;

FIG. 6 is a flow diagram of a method for determining functional activitylevel from step data in accordance with one embodiment of the presentinvention;

FIG. 7 is a flow diagram of a method for determining the stability frommoment data in accordance with one embodiment of the present invention;

FIG. 8 is a representative home Web page of a Web Site in accordancewith one embodiment of the present invention;

FIG. 9 is a representative Web page to create a new account inaccordance with one embodiment of the present invention;

FIG. 10 is a representative Web page to create a new account inaccordance with one embodiment of the present invention;

FIG. 11 is a representative notification that a new account has beensuccessfully created in accordance with one embodiment of the presentinvention;

FIG. 12 is a representative Web page to enter client data into an onlinedatabase in accordance with one embodiment of the present invention;

FIG. 13 is a representative graphical user interface of a localfunctional assessment tool in accordance with one embodiment of thepresent invention;

FIG. 14 is a representative window of a local functional assessment toolfor entering client information in accordance with one embodiment of thepresent invention;

FIG. 15 is a representative window of the local functional assessmenttool to notify of start time and recording parameters in accordance withone embodiment of the present invention;

FIG. 16 is a representative window of the local functional assessmenttool to notify of the start time and recording parameters in accordancewith one embodiment of the present invention;

FIG. 17 is a representative window to log into a Web site in accordancewith one embodiment of the present invention;

FIG. 18 is a representative Web page to display the client database inaccordance with one embodiment of the present invention;

FIG. 19 is a representative Web page for collecting clinicalobservations in accordance with one embodiment of the present invention;

FIG. 20 is a representative notification indicating that step data hasbeen successfully uploaded to the remote server in accordance with oneembodiment of the present invention;

FIG. 21 is a representative Web page to manage clients in accordancewith one embodiment of the present invention;

FIG. 22 is a representative Web page to report the activity level of alower limb amputee; and

FIG. 23 is a graphical representation of a model of stability plottedagainst data collected for a step in both the coronal and sagittalplanes.

DETAILED DESCRIPTION

Disclosed herein is a system and a method for assessing the functionalactivity level of a lower limb amputee. Also disclosed is a system and amethod for assessing the instability of a lower limb amputee wearing aprosthesis.

Referring to FIG. 1, a system is illustrated for both assessing thefunctional activity level and the instability of a lower limb amputee112 wearing a prosthesis. The system includes a user computer 104(computer) connected through a communication network, such as theInternet 102, to a server computer 110 (server). The system furtherincludes a docking station 106 (dock) in communication with the computer104. The system includes a pedometer 108 (step counter). The systemincludes a moment sensor 109. Either or both of the pedometer 108 and/orthe moment sensor 109 may be worn by a lower limb amputee 112.

The pedometer 108 can detect and record the steps the wearer takes overa period of time, and provide the number of steps taken over aninterval. During normal walking, a step cycle includes a stance phasewhen the foot is in contact with the ground and a swing phase when thefoot is not in contact. The pedometer 108 is constructed to determineand record the number of steps taken by a wearer during selected timeperiods. The information is then used to determine a functional level ofactivity. The pedometer 108 may include an optical transmitter/receiverto permit the pedometer 108 to be optically coupled to the dockingstation 106 which, in turn, is connected to the computer 104, therebyallowing transmitting information to and receiving information from thecomputer 104. A suitable pedometer 108 for use in the present inventionis described in U.S. Pat. No. 5,485,402, issued to Smith et al., and isfully incorporated herein expressly by reference.

As described in the '402 patent, the pedometer 108 may include a sensor,such as an accelerometer, for providing an acceleration signalindicative of the acceleration of the pedometer 108, which can becorrelated to the acceleration of the foot and/or ankle of a wearer. Thesensor may also be constructed from a dielectric angle sensor, or amemory switch. Furthermore, the pedometer 108 may comprise multiplesensors for sensing movement relative to one another. The sensor ofpedometer 108 provides a signal to a step determination unit. The stepdetermination unit is generally software and hardware responsive to theacceleration or other signal for determining whether the wearer hastaken a step. The step determination unit includes a step counterinterface coupled to one or more registers. The registers are providedfor recording step determination data such as, for example, a minimumacceleration data unit indicating a minimum acceleration required beforethe activity will be counted as a step, a maximum acceleration data unitindicating a maximum acceleration that will be tolerated before theacceleration signal is discounted, and a minimum time unit indicatingthe minimum duration that the pedometer 108 must be accelerating beforea step will be counted. The pedometer 108 provides the wearer with theability to program the registers so that the sensitivity of theregisters may be more or less in order to increase the accuracy andavoid false positives (step counted when no step taken) and/or falsenegatives (step taken but not detected). The pedometer 108 includes amemory for storing the step determination data and a clock unit fordetermining the time period over which the steps are counted. Thepedometer 108 includes read-only memory (ROM) for storing program andinstruction data for controlling the operation of the data processorcomputer within the pedometer 108. The pedometer also includes randomaccess memory (RAM) for storing data for programming the data processoras well as for recording data provided by the data processor computer.The memory is also constructed for storing a step rate data unit thatindicates the amount of time that the step signal will be ignored aftera step is counted. The step rate data unit thereby permits a user todetermine a gait, or a step rate (e.g., steps per minute, steps perhour, and the like). To determine the step count data, the dataprocessor counts the number of steps taken during each step rate timeinterval and records the number into memory. A new step count data unitis provided for each measurement time interval. The measurement timeintervals can be consecutive. However, the pedometer 108 may beprogrammable to specify nonconsecutive time intervals. The length of themeasurement time interval may be selected. Additionally, the pedometer108 can be programmed to begin monitoring at a specific time and endmonitoring at a specific time. Alternatively, the pedometer 108 may beprogrammed to monitor a selected time period of each day for a selectednumber of days. The pedometer 108 includes a communication interface,such as an optical transmitter/receiver for transmitting and receivingoptical signals, circuits for converting the optical signals toelectrical signals, and for converting the electrical signals to opticalsignals. However, the pedometer 108 may employ other means ofcommunicating information to and receiving information from the computer104. For example, the pedometer 108 may have a wired interface, such asa Universal Serial Bus (USB), or a wireless radio frequency interface,such as Bluetooth. Finally, the pedometer 108 is used to collect steprate data for use in calculating the functional activity level of alower limb amputee as described further below. When used for the purposerelating to determining the functional activity level, the pedometer 108can be “locked” to prevent alteration or programming by anyone otherthan a clinician treating the amputee.

The moment sensor 109 is a device capable of measuring moments (forcestending to rotate an object) experienced by the socket of a prosthesislower limb. As used herein, “socket” refers to a component of aprosthetic limb into which the residual portion of the living limb thathas been amputated fits into. Lower limb amputees may be classified astranstibial, meaning the amputation is below the knee, or transfemoral,meaning the amputation is above the knee. There are otherclassifications, but these two are the most common. A socket fits overthe residual limb. The socket is in turn connected to a prosthetic foot.As can be imagined, the fit and contact between the residual limb andthe socket is important for the comfort and stability of the wearer.U.S. Patent Application Publication No. 2008/0139970, issued to Macomberet al., incorporated in its entirety herein by reference, discloses amoment sensor for measuring the moments acting on the socket. The momentmeasurement information may then be used in calculating an optimalspatial alignment of the prosthesis socket. A prosthesis generallyincludes at least one articulable component that is adjustable to movethe socket forward and backward and side to side to change the spatialalignment of the socket in comparison to the shank and foot. When theprosthesis is out of spatial alignment, walking can be a difficult asforces may push the wearer to either side or forward or backward duringevery step, thus, fatiguing the wearer quickly as he or she tries tocompensate for the misalignment. A spatial alignment is desired thatoptimizes the comfort and stability of a wearer. An ideal spatialalignment, derived from a training set of data, defines a characteristiccurve or sets of curves of moments in the coronal and sagittal planes,plotted from the time the prosthetic foot makes initial contact with theground through the time the foot lifts off from the ground. The momentsensor 109 is placed on the prosthesis between socket 20 and shank 60,such as at the base of the socket 20, to measure the moments experiencedat the socket 20. The moment sensor 109 gathers moment information thattends to bend the prosthesis either to the left or right (coronalplane), or forward or backward (sagittal plane) as the prosthesis isused to walk on the ground. The moment sensor 109 includes four sets ofstrain gauges placed along the sides of four beams connected to a pylonthat experiences the forces from the socket since the pylon connects tothe shank, which leads to the foot. As the amputee steps with theprosthesis, the moments experienced at the socket are recorded and maybe compared to an ideal model of alignment. The model of alignment isderived from a set of training data that describe the moments ofamputees with properly aligned prosthesis. The data collected from awearer with a misaligned or aligned prosthesis is then compared againstthe model via the use of statistical algorithms to analyze for closenessbetween the recorded data and the model. The relationships between themodel and the socket moments are known so that it becomes possible toprovide instructions to bring a misaligned prosthesis closer to themodel.

The moment sensor 109 includes an anterior beam, a posterior beam, aright and a left beam. Each beam further includes a first and secondstrain gauge attached to the side surface of the beam. Two sets of fourstrain gauges are arranged into two balanced bridges, each with apassive/resistive temperature component in series with each bridge so asto develop a voltage representative of the total bridge resistance. Theorientation of the balanced bridges allows for calculation of momentsinto two orthogonal planes, such planes being the sagittal plane(anterior/posterior plane) and the coronal plane (right/left plane). Thearrangement of the strain gauges in oppositely placed pairs reduces oreliminates the moments experienced along the third (transverse orhorizontal) plane orthogonal to the other two. The upper side of thesensor 109 is attached to the bottom of the socket 20 and the bottomside of the sensor 109 is attached to the shank 60. For this purpose,the sensor 109 includes an inverted “pyramid” supported from ahemispherical dome. The sensor 109 rests on a concave matching cup ofthe shank and so provides articulation of the transverse plane, thuschanging the spatial alignment between the socket 20 and the rest of theprosthesis. The moment sensor 109 also includes electrical components topower and convert voltage differences measured by the strain gauges intomoments along both the coronal and sagittal planes. Also provided withthe moment sensor 109 is a master unit. The master unit may include thepower supply, radio transmitter, and/or any other type of wirelesscommunication system, such as optical systems for transmitting andreceiving data wirelessly to and from a computer. In this case, a masterunit attached to the moment sensor 109 may include optical componentsthat allow the transfer of data to and from the moment sensor 109 to thedocking station 106 and computer 104, similar to the pedometer 108. Themaster unit may include a gyroscope, a central processing unit orcomputer and a memory to record the moment data gathered while a patientwalks along the ground.

Referring to FIG. 2, the computer 104 includes a processing unit 204, adisplay 206, a memory 208, and a network interface. The memory 208generally comprises a random access memory (RAM), a read-only memory(ROM), and a permanent mass storage device, such as a disk drive. Thememory 208 stores program code and data necessary for operating a Webbrowser 210, for running and operating a “local” functional assessmenttool 212, for running and operating a local stability assessment tool214, and various device drivers 216, such as for communicating with thedocking station 106. The applications running on the computer may bedescribed in the context of computer-executable instructions, such asprogram modules being executed by the computer 104. Generally described,program modules include routines, programs, applications, objects,components, data structures, and the like that perform tasks orimplement particular abstract data types. “Local” as used herein refersto the computer 104, as opposed to “remote,” which describes the server110. The Web browser 210 can be any Web browser known in the art such asNetscape Navigator® or Microsoft Internet Explorer®. It will beappreciated that the components in the memory 208 may be stored on acomputer-readable tangible medium and loaded into the memory 208 of thecomputer 104 using a drive mechanism associated with a computer-readabletangible medium, such as a floppy or DVD/CD-ROM drive.

The computer 104 is connected to the server computer 110 through anetwork, such as the Internet 102. As is well understood, the Internet102 is a collection of local area networks (LANs), wide area networks(WANs), remote computers and routers that use the transmission controlprotocol/Internet protocol (TCP/IP) to communicate with each other. TheWorld Wide Web (www) is a collection of interconnected, electronicallystored information located on servers connected throughout the Internet102. In accordance with one embodiment disclosed herein, a prosthesisclinician using the computer 104 can assess the functional level ofactivity and/or stability of a client (amputee) over the Internet 102via a Web browser by communication to the remote server computer 110 andmay pay for receiving a determination and reports relating to a client'sfunctional level and/or stability. The computer 104 can be any number ofcomputer systems, including, but not limited to, work stations, personalcomputers, laptop computers, personal data assistants, servers, remotecomputers, etc., that is equipped with the necessary interface hardwareconnected temporarily or permanently to the Internet 102. Those ofordinary skill in the art will appreciate that the computer 104 could beany computer used by a prosthesis clinician to communicate with theremote server 110 to send and receive information relating to a client'sfunctional activity level or stability. Additionally, those of ordinaryskill in the art will appreciate that the computer 104 may include manymore components than those shown in FIG. 2. However, it is not necessarythat all of these generally conventional components be shown in order todisclose an illustrative embodiment for practicing the presentinvention. For example, the computer 104 may include an operatingsystem, such as the Windows® operating system. As shown in FIG. 2, thecomputer 104 includes a network interface 202 for connecting to a LAN orWAN, or for connecting remotely to a LAN or WAN. Those of ordinary skillin the art will appreciate that the network interface 202 includesnecessary circuitry for such a connection, and is also constructed foruse with the TCP/IP protocol, the particular network configuration ofthe LAN or WAN it is connecting to, and a particular type of couplingmedium. The computer 104 is also connected to the docking station 218via any communication protocol compatible with both the computer 104 andthe docking station 218.

FIG. 3 shows the various components of the server computer 110. Those ofordinary skill in the art will appreciate that the server 110 includesmany more components than those shown in FIG. 3. However, it is notnecessary that all of these generally conventional components be shownin order to disclose an illustrative embodiment of practicing thepresent invention. As shown in FIG. 3, the server 110 includes a networkinterface 302 for connecting to a LAN or WAN, or for connecting remotelyto a LAN or WAN. Those of ordinary skill in the art will appreciate thatthe network interface 302 includes necessary circuitry for such aconnection, and is also constructed for use with the TCP/IP protocol,the particular network configuration of the LAN or WAN it is connectingto, and a particular type of coupling medium. The server 110 includes aprocessing unit 304, a display 306, and a memory 308. The memory 308generally comprises a random access memory (RAM), read-only memory(ROM), and a permanent mass storage device, such as a hard disk drive,tape drive, optical drive, floppy disk drive, or combination thereof. Inone embodiment, the memory contains a client and medical recordsdatabase 314 which includes information relating a list of patients andeach patient's medical records, including, but not limited to, step dataand stability data and other information and associated reports. Theserver 110 memory may host a Web site containing a multiplicity of Webpages. The Web site provides a Web service to allow users to manage themedical records of amputee clients, and specifically to determine thefunctional activity level and instability or stability of lower limbamputees. The memory 308 also contains a remote functional assessmenttool 310. “Remote” as used herein is used to denote components found onthe server 110, and “local” is used to denote components found on thecomputer 104. The remote functional assessment tool 310 receives inputstep data and processes the data and outputs a functional level ofactivity of a lower limb amputee client. Also included in the memory 308is a remote stability assessment tool. The remote stability assessmenttool 312 receives stability data (i.e., moment data), processes themoment data, and provides a level of instability (or stability) of alower limb amputee client.

Communications between the computer 104 and the server computer 110 maybe encrypted via the generation of an encryption key pair comprising asecret key and a public key. For example, a secure socket layer (SSL)protocol is used for establishing a secure connection. SSL uses publickey encryption incorporated into the Web browser 210 and server 110 tosecure the information being transferred over the Internet 102. Theencryption, decryption and transmission of encrypted data over theInternet 102 using a public and private key is a well know operation.

Having described the components of a system used to assess thefunctional activity level and instability of a lower limb amputeeclient, a method to both assess the functional activity level andinstability will be described.

Referring to FIG. 4, a method 400 for assessing the functional activitylevel of a lower limb amputee is illustrated. Assessing the functionalactivity level is important since knowing the activity of the client isuseful in prescribing the appropriate type of components that will beused in manufacturing the prosthesis. For example, a high level activityindicates that a prosthesis needs to be built with certain components,such as energy storage/release capability, as well as lighter, strongercomponents. A low functional activity level indicates the client mayrequire a prosthesis that does not include such components. Thefunctional activity level assessment as disclosed herein uses thepedometer 108 to gather data relating to the number of steps over aspecific time interval. The data is then arranged into specific timeintervals to show a histogram of the number of steps in each interval.“Step” as used herein refers to the act beginning with placing the heelof the foot on the ground through the lifting of the toe or foot off theground.

The disclosed method uses the system illustrated and described inFIG. 1. The system uses a pedometer 108, a suitable pedometer is the onedescribed in U.S. Pat. No. 5,485,402, incorporated herein by referencein its entirety. However, other pedometers capable of keeping track ofthe number of steps and time intervals may be used. The system mayinclude the docking station 106 that can optically receive the datacollected by the pedometer 108 and communicate the data to the computer104. However, in other embodiments, the pedometer may communicatedirectly with the computer 104 or even the server 110 through theInternet. The computer 104 communicates via the Internet 102 with theserver 110 to provide the data collected with the pedometer 108 andreceives results from the server 110 using the local and remotefunctional assessment tools 212 and 312 stored in the computer 104 andthe server 110, respectively. The server 110 provides a service in theform of hosting a Web site to store the list of clients, the clients'medical records, including the data collected using the pedometer 108and moment sensor 109, provide for the assessment of the activity leveland instability of clients, generate reports, provide for the creationof accounts, provide for the downloading of the local functionalassessment tool, and collect payment for the use of the service. Thelocal functional assessment and stability assessment tools 212, 214perform such activities as device setup and data reading in connectionwith the pedometer 108 and moment sensor 109. The remote functionalassessment and stability assessment tools 310, 312 perform functionssuch as online remote storage of step and moment data, medical data andprocessing the step and moment data, and presenting the results througha Web site for consumption and analysis. The remote functional andstability assessment tools 310, 312 also offer the ability to manageclient information. Most of the functionality resides on the Web siteand can be accessed through the Web browser 210. This allows the localfunctional and stability assessment tools 212, 214 to remain small andeasy to install and be used on most of the commonly used computerplatforms. All the communications between the local functional andstability assessment tools 212, 214 and the server 110, as well asbetween the Web browser 210 and the Web site is encrypted, thusproviding for security. The data is securely stored on the server 110. Aclinician will only have access to the information that they themselvesentered into the system. This is managed by creating accounts for eachof the clinicians.

Referring now to FIG. 4, which illustrates a method for determining thefunctional activity level of lower limb amputee, step 402 is forcreating a user account to use a Web site for determining the functionalactivity level and instability of a lower limb amputee client. The user,a clinician for treating amputee clients, begins by opening the Webbrowser 210 on the computer 104 and navigates to a particular Web sitethat supports a Web service for assessing the functional activity leveland/or stability of lower limb amputee clients. The server 110 may hostthe Web site. FIG. 8 is a representative Web page 800 that may bedisplayed in order for the first-time user to create an account. The Webpage includes a menu item entitled “Create Account.” The user moves apointer or a cursor over the menu item “Create Account” and selects it.Upon selecting the “Create Account” item, a Web page may be displayed,such as the Web page 900 illustrated in FIG. 9. The Web page 900 of FIG.9 requests personal information. Some of the information may be optionaland can be edited at a later point in time. After entering the requiredand/or optional information, the user moves the pointer to the “Next”button and selects it. After selecting the “Next” button, a Web page maybe displayed, such as the Web page illustrated in FIG. 10. In the Webpage 1000, the user will select a user name and password. In oneembodiment, once the user name is chosen, the user name cannot bechanged later. Preferably, a strong password is chosen that is casesensitive, contains a minimum of seven characters and at least onenon-alphanumeric character. The user is prompted to enter an e-mailaddress that is unique to the Web site. The Web site checks and verifiesthat the e-mail is unique. After completing registration, the user willbe presented with a successful account creation notice, such as themessage 110 illustrated in FIG. 11, and an e-mail confirming the accountcreation may be sent to the e-mail address.

Referring to FIG. 4, from block 402, the method enters block 404. Block404 is for the user to enter client information. Using the Web browser,the user navigates to a Web page that includes a menu including theoption to “Manage Clients” from the “Data Management” group. Uponselection of the “Manage Clients” item, a Web page such as the Web page1200 of FIG. 12 may be displayed. The user can enter informationcorresponding to each client for which they plan to enter step or momentdata. The user may enter the personal information of the client in eachfield. After the information is added to the data input fields, the usermay move the pointer over the “Add Client” button and select it. Afterselecting the button, the client will be added to the online database314 in server 110. The Web page 1200 allows for clearing all theinformation at once by moving the pointer over the “Clear” button andselecting it. The Web page 1200 also allows for sorting clients by IDnumber, first name, last name, diagnosis, and creation date by movingthe pointer over the respective button and selecting it.

Data entered up to this point in the method relates to the creation of auser account and to the creation of a list of an online client database.In order to begin collecting the step data that will be used tocalculate the functional activity level, the user is required to loadthe local functional assessment tool onto the user computer 104. It iscommon practice to download applications by establishing a connection tothe Internet 104 and then downloading the application onto the usercomputer 104. From step 404, the method enters step 406. In step 406,the user can download and install the local functional assessment toolfrom the Web site 316 and configure the computer 104 to operate thedocking station 106. Part of the installation may include installingdevice drivers needed to communicate with the docking station 106 and aserial port driver, such as USB. The docking station 106 may bephysically connected to the computer 104 through a USB cable. Thecomputer 104 has an operating system such as the Windows® operatingsystem. The operating system may automatically detect the connection toa new device and search for the appropriate device driver. From step406, the method enters step 408, for connecting the pedometer dock.

After the hardware and software are installed and configured, the usermay then start the local functional assessment tool in step 410. As partof the installation of the local functional assessment tool, an icon maybe generated that appears on the computer screen. Moving the pointerover the icon and selecting it will start the local functionalassessment tool 212. A window, such as the window 1300 illustrated inFIG. 13, may appear on the display of the computer 104 when the localfunctional assessment tool is started on the computer 104. The windowrepresents a graphical user interface of the local functional assessmenttool that may include a “Start Recording” icon 1302, a “Read and Upload”icon 1304, an “Online Database” icon 1306, and a “Quit” icon 1308.Selecting the “Start Recording” icon 1302 starts a process forconfiguring and setting up the pedometer 108 and dock 106 to program thepedometer 108 with instructions regarding the start time and stop timeof the recording interval or intervals. Selecting the “Read and Upload”icon 1304 starts a process for retrieving the information from thepedometer after the step data has been collected. Selecting the “OnlineDatabase” icon 1306 starts a process for navigating to a Web sitecontaining secure client medical records, including the step data andmoment data and associated reports. Selecting the “Online Database” icon1306 will start the Web browser 210 to interface with the remote server110 that stores the database. Selecting the “Quit” icon 1308 quits thelocal functional assessment tool 212 and closes the window 1300. Asdiscussed above, preferably, the pedometer 108 is programmable toreceive instructions concerning the duration and intervals over whichsteps are to be recorded, including the start and the stop times. Instep 410, the user starts the local functional assessment tool 212 tobegin the process of recording of data. The user may move the pointerover the “Start Recording” icon and selecting it. The user may beprompted to place the pedometer 108 in the docking station 106 andverify that he or she has done so by selecting an “Okay” button. Thefunctional assessment tool verifies that pedometer 108 is configured forrecording data. After verification, a window may be displayed, such asthe window 1400 illustrated in FIG. 14. The window 1400 may prompt theuser to provide information such as, client height, whether the clientengages in quick stepping, such as participating in sports, dancing,etc., the walking speed of the client relative to people of similarheight, the range of speeds, and leg motion. Representative choices forwalking speed are “Slow,” “Fast,” and “Normal.” The user may select one.Representative choices for range of speeds are “Uses a moderate range ofspeeds,” “Regularly uses both extremes,” and “Rarely varies pace.” Theuser may select one. Representative choices for leg motion that describethe appearance of the client's leg motion are “Normal,” “Fidgety orDynamic,” “Gentle or Geriatric,” and “Severely Impaired.” The user mayselect one. For each entry, the user may be provided with a menuproviding a limited range of answers. The choices selected are used toadjust the sensitivity of the pedometer 108 to acceleration of the leg,both in magnitude and duration. Once all the information is entered, theuser may move the pointer over the “Start” button and select it. Thelocal functional assessment tool 212 will then download the instructionsto the pedometer 108 through the docking station 106. While the localfunctional assessment tool 212 is downloading instructions to set up thepedometer 108, a progress notification may appear on a window, such asthe window 1500 illustrated in FIG. 15. The window 1500 will indicatesuch information as the time the pedometer 108 will start to record dataand the particular settings of the client. Once the pedometer 108 setupis completed, a confirmation window may be displayed such as the window1600 illustrated in FIG. 16, showing the time the step recording willbegin and the duration of the recording.

From step 410, the method enters step 412. During step 412, the clientcollects the data. The pedometer 108 may be worn by the clientcontinuously, day and night, for the selected period of time. Duringthis period, every time the client completes a step, the pedometer 108will count the step and may note the time interval in which it wasrecorded. Additionally, the time may also be recorded. After therecording period is at an end, the client may return the pedometer 108to the user clinician.

From step 412, the method enters step 414. Step 414 is for logging intothe system to begin downloading the data to the online database 314.Once the patient has worn the pedometer 108 for the selected period oftime and has returned the pedometer, the data may be downloaded from thepedometer 108 and uploaded to the Web site 316. This process is carriedout using the computer 104 connected to the Internet 102 and the localfunctional assessment tool 212. The pedometer 108 may be placedalongside the dock 106 to enable optical communications from thepedometer 108 to the dock 106. The user may once again start the localfunctional assessment tool 212 by selecting an icon on the desktop ofcomputer 104. The user may select the local functional assessment toolicon and a window, such as the window 1300 illustrated in FIG. 13, maybe displayed. The user moves the pointer over the “Read and Upload” icon1304 and selects it. This will bring up a window to log in, such as thewindow 1700 of FIG. 17. The local functional assessment tool 212 willask the user to log into the system using the previously createdaccount. The user enters the user name and password for the account.After successfully logging in, the list of clients that have beenpreviously registered may be displayed on a window such as the window1800 illustrated in FIG. 18. In step 416, the user moves the pointerover the selected client whose data is to be uploaded. If the client isnot in the database, a new client may be created by moving the pointerover the “Add Client To Web Account” button and selecting it. The sameprocedure as described before for adding a new client will start.

After the user selects a client, the user can move the pointer over the“Next” button and select it. Step 418 is for entering clinicalobservations. In step 418, the local functional assessment tool 212 willask the user to enter the client's weight and the user's assessment ofthe functional activity level of the client. In the United States, thefunctional levels have been assigned designations K0 through K4. Whilethe discussion of the functional activity levels of lower limb amputeesis stated in terms of K levels, it should be readily apparent that otherdesignations can be used according to the present invention. A window,such as the window 1900 illustrated in FIG. 19, may be displayed forthis purpose. Once the fields are populated, the user may move thepointer over the “Next” button and select it. Upon selecting the “Next”button, the user will be asked to confirm that the pedometer 108 hasbeen placed on the dock 106. Step 420 is for placing the pedometer 108alongside the dock 106. The functional assessment tool 212 may promptthe user to verify the correct placement of the pedometer 108. Once theuser confirms the pedometer 108 is correctly placed on the dock 106,step 422 is entered for reading the data and transmitting the data overthe Internet 102 to the remote server 110. When the data upload iscomplete, the user may be notified the data transfer has beensuccessfully completed by displaying a notification window, such as thewindow 2000 illustrated in FIG. 20.

From step 422, the method enters step 424. Step 424 is for opening theWeb browser to log onto the Web site 316 associated with the remotefunctional assessment tool 312. The local functional assessment tool 212may be used to open the Web browser to communicate to the server 110.The user navigates via a Web browser to log into the Web site 316 togain access to the remote functional assessment tool. The user logs intothe Web site 316 using the same user name and password as the locallogin. A Web page, such as the Web page 2100 illustrated in FIG. 21, maybe displayed to the user on the computer 104. To receive an assessmentof the functional activity level, the user moves the pointer over the“K-level Report” menu option under the “Data Management” group in theleft side of the Web page 2100. This will bring up the list of activeclients. The user moves the pointer over the name of the client aboutwhom the user desires to receive a report. The client may have aplurality of data sets that have been uploaded for various time periods.The user will be able to distinguish among the data sets based on therecording interval or dates. The user has the option of selecting thetime interval for which to receive a report.

The first time a particular report is requested, the user may have topay a user fee to receive the report. If the user has not paid for areport, a checkbox under the “Paid” column of the report will not bechecked, and the “Get Report” feature may be disabled and shown grayedout. The Web page will ask the user to explicitly agree to the chargesfor the cost of the report. Transactions involving payment in exchangefor goods over the Internet has become a common channel for providinggoods to users of such goods. The Web site 316 disclosed herein uses anyof the secure forms of payment for such transactions. Following theinitial payment for a report for one data set, for example, the userwill be able to access the report at any time in the future for noadditional charge. After selecting an “Agreement” checkbox, the “GetReport” feature will be active. The user can move the pointer over thebutton and select it to retrieve the report. The Web page 2200illustrated in FIG. 22 shows a representative functional activity levelreport. The Web page 2200 may include options for printing and savingthe report.

The remote functional assessment tool uses four descriptors to calculatea functional activity level (K-values in the report). The differentdescriptors used for the functional activity level (K-level)determination are: cadence variability, potential to ambulate,ambulation requirement, and clinical observation. The number reportedfor each represents how a client, for a particular monitoring session,matches up versus ADL requirements and other clients in the database.The ADL requirements are defined by a number of common activities ofdaily living, such as cooking, cleaning, commuting, and working. It isnormal for a client to score higher in some categories than others andeach of the four descriptors gets an equal “vote” as to the ultimatereported K-value. The system uses an equal vote because the client isnot penalized for their particular requirements. For instance, cadencevariability scores equally with ambulation requirement. Also, themeasures are “continuous” variables. That is, the remote functionalassessment tool 312 calculates how the descriptor maps to the K-level in1/10th increments. This gives the measure much more sensitivity to thecondition and change of the patient. A patient with a measure of 2.7 isreally a 2 rising to 3, or a 3 falling, etc.

The remote functional assessment tool 312 calculates cadence variabilityas the variance in the amount of time that the client spends at threelevels of step rate (0-15 steps/minute, 15-40 steps/minute, and 40+steps/minute). These ranges of step rates are representative ofdifferent kinds of activity. The rates are then mapped to a database ofrepresentative activities of K1 through K4 prosthesis users. Forexample, the recorded step data is compared statistically to a sample ofpreviously measured amputee activities in order to categorize the ratesas reflecting the previously measured activities of others. This will beused to provide a number.

The second descriptor, potential to ambulate, is calculated bymonitoring the prosthesis continuously, such as a week, for example. Ifthe data shows step activity during the week, this is an indication ofpotential to ambulate even if the activity is not sustained. Forexample, the peak activity is selected over a short period of time, suchas several minutes (5 minutes in one embodiment), whenever it may occurthroughout the interval monitored. This may be compared statistically toa sample of previously measured amputees in order to arrive at a number.No step activity would be seen if the person is completely unable toambulate at the time, but it is effective with patients returning tofunction. In either occasion, it comprises one vote and is averaged outby the clinical observation.

The clinical observation is the input entered during step 418 of themethod. If the user is confident that the patient can return to a K4level, but the potential measured at the time is K2, then, the result oftheir potential comes out as K3, which is probably a reasonable place tostart if the patient is currently unable to walk with a normally variedcadence. The clinical observation provides an activity level basedgenerally known method of assessing an activity level. The methoddisclosed herein uses such number and provides additional descriptorscalculated from step data to provide a more objective assessment.

The fourth descriptor, ambulation requirement, looks at the maximumnumber of steps the person will take with their prosthesis during a20-minute window whenever it occurs throughout the day. The amount ofsustained use of the prosthesis is an accurate indicator of whether theyhave need to transfer, ambulate in the home, ambulate in the community,or have needs in excess of ADL. Once a value is received for each of thefour descriptors, the values are added and divided by four to arrive atthe average value, which is reported as the K-level of activity in thereport. As can be appreciated, the reported level of activity is basedon measured step data performed by the client over an extended period oftime and can provide a more reliable value as opposed to a purelyclinical assessment.

Referring to FIG. 6, a method 600 is illustrated for the calculation ofthe functional activity level. As mentioned above, functional activitylevels for lower limb amputees in the United States are measured byassigning a K value, from K0, no activity, to K4, as defined in theBackground section of this application. In step 602, the systemcalculates the cadence variability. From step 602, the system entersblock 604. In block 604, the method calculates potential to ambulate.From step 604, the method enters step 606. In step 606, the methodcalculates the ambulation requirement. From step 606, the method entersstep 608. In step 608, the method retrieves the clinical observation ofthe K level. From step 608, the method enters step 610 to average thefour previous inputs valued from greater than 0 to 4. The average is thereported functional activity level in step 612.

As discussed above, the computer 104 and remote server 110 may includeboth a functional assessment tool as well as a stability assessmenttool.

Referring to FIG. 5, a method for calculating the instability (orstability) of a lower limb amputee is illustrated. Stability aninstability may be viewed as the same in this disclosure. The methodillustrated in FIG. 5 uses the moment sensor 109 to collect data inplace of the pedometer 108 that collects step rate data. Accordingly,the method illustrated in FIG. 5 employs many similar steps as themethod illustrated in FIG. 4. The difference between the methods beingthat to obtain a measure of instability, the data collected is momentdata measured for the length of one or more steps. As discussed above, astep as used herein refers to the period from the time that theprosthesis foot makes contact with the ground to the time the prosthesisfoot is lifted off from the ground. The moments that act in the coronaland sagittal planes on the prosthesis socket during each step arecollected and recorded in the memory of the moment sensor 109.

In step 512 of method 500, moment data is collected instead of step ratedata. The moment sensor 109 communicates via the same or differentdocking station 106. The moment data that is collected is for thecalculation of instability. Referring to FIG. 7, a method is illustratedfor calculating the stability of a lower limb amputee patient.

In block 702, the method retrieves a model of stability created from atraining data set. Referring to FIG. 23, a graphical representation of amodel of stability is illustrated by the shaded areas 2406 and 2420denoting the acceptable range of moments for stability in theanterior/posterior (sagittal) plane 2402 and the right/left (coronal)plane 2414. Moments are plotted for two steps in both the coronal andsagittal planes from the time of initial contact (IC) of the foot to thetoe off (TO) from the ground. One embodiment for deriving a model ofstability is by using a training data set collected from a plurality oflower limb amputees with known stabilities. Stability can be expressedas a coefficient of variance of the mediolateral movement over timeduring the stance phase of gait. The ideally stable prosthesis patientsare permitted to walk to collect moment data representative of the idealstability profile. After testing numerous ideally fitted prostheses, thedata is collected and used to create the model of stability. Statisticalmethods are known for creating models that describe the ideal behaviorfrom large amounts of data. Another simplified method is to collectmoment data from the patient with a prosthesis that is ideally fitted tothe patient and with which the patient can walk stably. This moment datathen becomes the standard to which all future prosthesis must conform tobe classified as stable.

From step 702, the method enters step 704. In step 704, the methodretrieves actual moment data of the client being analyzed forinstability. Referring to FIG. 23, the actual moment data represented bylines 2408 and 2410 I the sagittal plane and lines 2416 and 2418 in thecoronal plane may not lie within the boundaries of the model ofstability 2406 and 2420. The lines on the anterior/posterior plane andleft/right planes illustrate that there may be deviations of the actualmoment data from the model.

Instability is then a measure of the deviation or variance of the actualdata from the model. To analyze for instability, the analysis may takecertain “gait” variables into consideration. Gait variables arecharacterizations of information gathered during the step motion. Gaitvariables may include, but are not limited to some or all of theanterior/posterior moment and right/left moment at each 20% increment intime of the step phase, the maxima and minima of the anterior/posteriormoments and the right/left moments for the first and last 50% of thestep phase, the slope of the change in anterior/posterior moment andright/left moment during each successive 20% time increment, theintegrated anterior/posterior moment and right/left moment measured overthe period of each step phase. One or more of these gait variables arethen applied to the model of stability using a statistical analysistool.

The equations used in deriving the model of stability are derivedheuristically to minimize an external criterion called the predictionerror sum of squares, or PESS, for previously measured socket moments.

$\begin{matrix}{{P\; E\; S\; S} = {\frac{1}{N}{\sum\limits_{t = 1}^{N}( {y_{t} - {f( {x_{t},{\hat{a}}_{t}} )}} )^{2}}}} & (1)\end{matrix}$

Where N is the number of gait variable samples available, Y is thetarget stability, and a is an estimation of the combined parameters thatdescribe the instability. The equation derivations are achieved usingthe group method of data handling described by Madala and Ivakhnenko(Madala, H., and A. Ivakhnenko, “Inductive Learning Algorithms forComplex Systems Modeling,” CRC Press, Boca Raton, Fla., U.S.A., 1994),fully incorporated herein expressly by reference. Solving the derivedmodel equations with the gait variables results in a numeric estimationof the instability. For robustness, estimations from each of theequations become a vote added to a more generalized estimation of thestability. Stability is signified by decreased variability in step tostep movement sessions time plots. A unit less (nondimensional) indexnumber can be assigned based on population statistics.

After conclusion of the functional level assessment and/or theinstability assessment, the user has information from which to prescribea prosthesis matching the activity level or instability of the user. Forexample, after calculating an activity level of 4, the user mayprescribe a prosthesis having lightweight, high strength materials foruse in building the prosthesis. Also, a foot having an energystorage/release component may also be prescribed. On the other hand, ifthe functional assessment level is a 1, the user may prescribe aprosthesis having less exotic materials, such as stainless steel oraluminum materials, and basic unmodified rubberized materials as thefoot with minimal energy storage/release capability. The method fordetermining stability assists the clinician to track the progress of anamputee to determine whether the amputee's progress is increasing todecreasing.

While illustrative embodiments have been illustrated and described, itwill be appreciated that various changes can be made therein withoutdeparting from the spirit and scope of the invention.

1-26. (canceled)
 27. A system for assessing an activity level of a user,comprising: a sensor configured to determine a metric of the user; amemory configured to store the metric of the user; a processor coupledto a server, wherein the processor is configured to adjust the sensor todetermine the metric of the user, and configured to receive from thememory the stored metric of the user; the server being in communicationwith the processor, and the server being configured to: receive themetric from the processor; and process the metric to provide a valuedeterminative of a functional ability of a user, wherein the value ofthe functional ability of the user is an average derived from at leasttwo values obtained from a group consisting of: a value representingcadence variability, a value representing potential movement of theuser, a value representing a movement threshold, and a valuerepresenting a clinical observation of the user.
 28. The system of claim27, wherein the server hosts a Website that provides at least oneselected from a group consisting of a service for determining the valueof the functional ability level of the user, a client manager tool, andan online database.
 29. The system of claim 27, wherein the servercomprises a remote functional assessment tool.
 30. The system of claim27, wherein the server determines, based on the metric, the valuerepresenting the cadence variability as a variance in an amount of timethat the user spends at a plurality of levels of a step rate in adefined period of time.
 31. The system of claim 27, wherein the serverdetermines, based on the metric, the value representing the potentialmovement of the user as a number of steps taken by the user in a definedperiod of time.
 32. The system of claim 27, wherein the serverdetermines, based on the metric, the value representing the movementthreshold as a maximum number of steps taken by the user in a definedperiod of time.
 33. The system of claim 27, further comprising: adocking station configured to couple the processor with the sensor,wherein the docking station communicates with the sensor.
 34. The systemof claim 27, wherein the functional ability value is usable to determinea prescription of components for a prosthesis.
 35. The system of claim27, wherein the determination of the value representing the cadencevariability or the value representing the potential movement of the userincludes a comparison of the metric for a sample of users.
 36. Thesystem of claim 27, wherein the metric is at least one selected from agroup consisting of step tracking, step activity, step rate, timeactivity, and time tracking.